Integrated circuits (ICs) include many tens of thousands of semiconductor devices including transistors are a cornerstone of modern microelectronic systems. The various regions of the transistors (e.g., source/drain and source/drain extensions) are formed by introducing dopant atoms into a semiconductor substrate using methods such as ion implantation. After the dopants have been introduced, they are electrically activated by subjecting the semiconductor substrate to one or more annealing processes.
Unfortunately, dopants have a tendency to diffuse or expand both laterally and vertically away from the profile as-introduced during annealing thereby increasing the dimensions of the various device regions. This outward diffusion of dopants is undesirable particularly as semiconductor devices are scaled down in size.
In addition, one of the major concerns in device scaling is the contact resistance between the silicide and the doped junction. The contribution of the silicide to junction contact resistance increases with further scaling of transistors. This undesirably leads to degradation of device performance.
From the foregoing discussion, it is desirable to provide devices with improved performance.